This invention generally relates to methods and devices for use during chemical or biological attacks, and more specifically, to methods and devices that help protect a building or other structure from contamination during chemical or biological attacks.
The recent demise of the cold war and decline in super-power tensions has been accompanied by an increase in concern over the viability of weapons of mass destruction such as chemical and biological (CB) weapons. CB weapons include chemical agents such as phosgene, nerve agents such as Sarin, and biological agents such as anthrax or small pox. CB weapons may be delivered to occupants within a building by releasing the agents within the building or external to the building but close to an air intake of the building. The air intake may be located near the ground, near the roof, or somewhere in between, depending on the building architecture. The building""s heating, ventilating, and air conditioning (HVAC) system may then rapidly deliver the released agent into and/or throughout the building. Agents may also be released within a public space of a building, and be dispersed to other, private areas of the same building via the buildings HVAC system.
In some situations, the building occupants may be given some warning before the release of an agent, either by prior knowledge or by agent sensors. In other situations, the building occupants may be given little or no warning, such as when the agent is released by a pedestrian held putative asthma inhaler activated near an air intake. In either case, it is desirable to evacuate the human occupants from the building or to a safe room within the building. Even if most inhabitants are able to evacuate, the building itself may very well become contaminated, and require a long time period to decontaminate, or even be permanently unusable. What would be desirable, therefore, are methods and apparatus for preventing or limiting the extent of the initial contamination of a building or parts of buildings.
The present invention includes systems for preventing or limiting the extent of the contamination of buildings, parts of buildings, equipment, etc., during and/or after an attack. This is preferably accomplished by selectively sealing off one or more building regions using inflatable bladders or other devices when a chemical or biological agent is detected. A harmful agent detector such as a chemical or biological detector (CBD) can be used in a manual mode to activate an alarm and rely on a human to initiate the system or can be used in conjunction with a controller system in an automatic mode to automatically initiate the system. The bladder may include a rapidly reacting chemical composition that rapidly creates a volume of gas sufficient to inflate a gas bag, which then seals off a desired building opening or region.
One class of expandable bladders includes envelopes formed of resilient material that may stretch slightly under pressure, or not at all. These resilient bags are preferably oversized relative to the building opening or region in which they are placed. The oversized bladders preferably have sufficient surface area to extend into the room region corners and occlude the opening or region. Another class of expandable bladders includes envelopes, preferably shaped envelopes, formed of a resilient material that more easily stretches under pressure. These resilient or elastic envelopes can preferably stretch into the corners of, for example, rectangular air ducts, rooms, or hallways to seal the corners of an opening or region.
Some inflatable occlusion devices are positioned along one wall of a building region. Other expandable bladders are pre-positioned between two corners of a building region and can be paired with another bladder or bladder portion disposed between two different corners of an opposing internal wall. Pre-positioned bladders can be held in place using mechanical, magnetic, or any other means. Pre-positioning bladders in a building region""s internal corners can provide corner and wall occlusion at the outset, leaving the building region interior either unoccluded or occluded by another inflatable occlusion device.
A preferred source of expansion gas includes chemical compositions that generate relatively large amounts of gas when a reaction is initiated, often by an electrical spark or rapidly heated wire. Gas may be supplemented or even supplanted by use of an expanding foaming agent. The foaming agent can be used in part to force a bladder into room, hallway, or duct corners to insure corner occlusion. The foaming agent can be used to make the bladder""s expansion at least semi-permanent, insuring that the room region will remain sealed even if gas leaks from the bladder. The foam is preferably rapidly expanding and hardening, and can be similar to foams used for in-place foam packing applications and home and building insulation applications.
In use, a building can be protected by selecting pre-identified protection zones or regions and disposing expandable occluding gas bladders within the protection zones or regions. Wiring can be extended to the pre-identified protection zones or regions, and may terminate locally through wires to a receiver which can be connected to an antenna. Chemical or biological detectors can be installed in select locations, including locations within rooms, hallways, entryways, ducts, plenums, and within other public areas of the building, and also can be located external to the building. Horizon detectors can be installed external to the building. The detectors can be either hardwired or linked with RF signals to a controller. The controller can either run in a manual mode, requiring a human to initiate bladder inflation, or an automatic mode using the controller to initiate bladder inflation.